Optical transducers and methods of making the same

ABSTRACT

A near field transducer (NFT) that includes a disk, the disk having a top surface, a side surface, and a center; a peg, the peg positioned adjacent the side surface of the disk; and a heat sink, the heat sink positioned on the top surface of the disk, and the heat sink having an effective center, wherein the NFT has a peg axis, which is defined by the location of the peg adjacent the side surface of the disk, and a non-peg axis, which is perpendicular to the peg axis, and wherein the effective center of the heat sink is positioned at about the center of the disk.

RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 13/248,927filed Nov. 10, 2011. The entire disclosure of this application isincorporated herein by reference.

BACKGROUND

“Heat assisted magnetic recording,” optical assisted recording orthermal assisted recording (collectively hereinafter HAMR), generallyrefers to the concept of locally heating a recording medium to reducethe coercivity of the recording medium so that an applied magneticwriting field can more easily affect magnetization of the recordingmedium during a temporary magnetic softening of the recording mediumcaused by the local heating. HAMR allows for the use of small grainmedia, which is desirable for recording at increased areal densities,with a larger magnetic anisotropy at room temperature assuring asufficient thermal stability. HAMR can be applied to any type of storagemedia, including for example, tilted media, longitudinal media,perpendicular media, and/or patterned media.

To locally heat up the media in HAMR, optical transducers, such as nearfield transducers (NFTs) are often incorporated into the head in orderto focus laser light to a nanometer sized area. An NFT is able toconfine light far beyond the diffraction limit by generating localizedsurface Plasmon (LSP).

The feature size of NFTs in a HAMR head is normally very small in orderto get the right resonance frequency, thermal spot size and highcoupling efficiency. For a “lollipop” shaped NFT, the disk size is oftenonly about 200 nm in diameter. NFTs are often embedded in waveguidematerials, which couple the laser light onto the NFT from outside.Waveguide materials normally have very poor thermal conductance. All ofthese factors result in enormous temperature increases at the region ofthe NFT, much higher than what thermal recording requires. This can leadto overheating and exceedingly elevated temperatures which can lead toreliability issues for HAMR heads. Therefore, there remains a need forNFTs that are less susceptible to overheating.

SUMMARY

Disclosed herein is a near field transducer (NFT) that includes a disk,the disk having a top surface, a side surface, and a center; a peg, thepeg positioned adjacent the side surface of the disk; and a heat sink,the heat sink positioned on the top surface of the disk, and the heatsink having an effective center, wherein the NFT has a peg axis, whichis defined by the location of the peg adjacent the side surface of thedisk, and a non-peg axis, which is perpendicular to the peg axis, andwherein the effective center of the heat sink is positioned at about thecenter of the disk.

Also disclosed herein is a near field transducer (NFT) that includes adisk, the disk having a top surface, a side surface, and a center; apeg, the peg positioned adjacent the side surface of the disk; and aheat sink, the heat sink including a main portion and a tip portion, andthe heat sink being positioned on the top surface of the disk, whereinthe NFT has a peg axis, which is defined by the location of the pegadjacent the side surface of the disk, and a non-peg axis, which isperpendicular to the peg axis, and wherein the tip portion of the heatsink is located substantially in the direction of the peg axis.

Also disclosed herein is a method that includes forming a firstphotoresist mask on a substrate, the first photoresist mask havinginside edges, the inside edges of the first photoresist mask defining afirst aperture, the first aperture having a first maximum width; forminga second photoresist mask on the first photoresist mask, the secondphotoresist mask having inside edges, the inside edges of the secondphotoresist mask defining a second aperture, wherein the second aperturehas a second maximum width that is smaller than the first maximum width;depositing near field transducer (NFT) material in at least the secondaperture; directionally depositing a cover material on at least theinside edges of the first and second photoresist masks forming a thirdaperture, the third aperture having a third maximum width, the thirdmaximum width being smaller than the second maximum width; depositingheat sink materials in at least the third aperture; and removing atleast a portion of the first photoresist mask, at least a portion of thesecond photoresist mask, at least a portion of the NFT material, atleast a portion of the cover material, and at least a portion of theheat sink material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a plan view of an example disc drive;

FIGS. 2A, 2B, and 2C illustrate an exemplary partial isometric view of anear field transducer (NFT) (FIG. 2A), a top down view of the exemplaryNFT (FIG. 2B); and a top down view of another exemplary NFT (FIG. 2C);

FIGS. 3A-3G show an article at various stages of a disclosed method toform a NFT; and

FIGS. 4A-4I show images of a NFT at various stages of the process thatwas fabricated using an exemplary disclosed method.

The figures are not necessarily to scale. Like numbers used in thefigures refer to like components. However, it will be understood thatthe use of a number to refer to a component in a given figure is notintended to limit the component in another figure labeled with the samenumber.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanying setof drawings that form a part hereof and in which are shown by way ofillustration several specific embodiments. It is to be understood thatother embodiments are contemplated and may be made without departingfrom the scope or spirit of the present disclosure. The followingdetailed description, therefore, is not to be taken in a limiting sense.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsare to be understood as being modified in all instances by the term“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the foregoing specification and attached claimsare approximations that can vary depending upon the properties sought tobe obtained by those skilled in the art utilizing the teachingsdisclosed herein.

The recitation of numerical ranges by endpoints includes all numberssubsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3,3.80, 4, and 5) and any range within that range.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” encompass embodiments having pluralreferents, unless the content clearly dictates otherwise. As used inthis specification and the appended claims, the term “or” is generallyemployed in its sense including “and/or” unless the content clearlydictates otherwise.

“Include,” “including,” or like terms means encompassing but not limitedto, that is, including and not exclusive. It should be noted that “top”and “bottom” (or other terms like “upper” and “lower”) are utilizedstrictly for relative descriptions and do not imply any overallorientation of the article in which the described element is located.

FIG. 1 is an isometric view of a disc drive 100 in which the presentlydisclosed optical transducers are useful. Disc drive 100 includes ahousing with a base 102 and a top cover (not shown). Disc drive 100further includes a disc pack 106, which is mounted on a spindle motor(not shown) by a disc clamp 108. Disc pack 106 includes a plurality ofindividual discs, which are mounted for co-rotation in a direction 107about a central axis 109. Each disc surface has an associated disc headslider 110 which is mounted to disc drive 100 for communication with thedisc surface. In the example shown in FIG. 1, sliders 110 are supportedby suspensions 112 which are in turn attached to track accessing arms114 of an actuator 116. The actuator shown in FIG. 1 is of the typeknown as a rotary moving coil actuator and includes a voice coil motor(VCM), shown generally at 118. Voice coil motor 118 rotates actuator 116with its attached heads 110 about a pivot shaft 120 to position heads110 over a desired data track along an arcuate path 122 between a discinner diameter 124 and a disc outer diameter 126. Voice coil motor 118is driven by servo electronics 130 based on signals generated by heads110 and a host computer (not shown). Disc drives 100 and heads 110 suchas those illustrated in FIG. 1 can include optical transducers, such asa near field transducer (NFT) (not shown in FIG. 1), including thosedisclosed and described herein.

FIG. 2A illustrates an exemplary partial isometric view of a near fieldtransducer (NFT). This exemplary NFT has what is commonly referred to asthe “lollipop” structure. The NFT 200 includes a disk 205. The disk isgenerally made of a plasmonic material. Exemplary materials that can beutilized for the disk 205 include, for example, gold (Au), silver (Ag),copper (Cu), aluminum (Al), and alloys thereof. In exemplaryembodiments, alloys of gold, including those discussed in co-pending,commonly assigned U.S. patent application Ser. No. 13/032,709, filed onFeb. 23, 2011; can be utilized. The disk 205 has a top surface 210 and aside surface 215. The disk may also be described as having a bottomsurface that is opposite the top surface 210 and is not shown in FIG.2A. The disk 205 also has a center 220.

An NFT 200 also includes a peg 225. The peg 225 can be generallypositioned adjacent the side surface 215 of the disk 205. If the NFT isdescribed as having a “lollipop” structure, the peg can be described asthe stick of the lollipop. The peg 225 can, but need not, be made of thesame material as the disk 205. In embodiments, the disk 205 and the peg225 are one continuous structure that was deposited simultaneously.

An NFT 200 also includes a heat sink 230. The heat sink 230 can bepositioned on the top surface 210 of the disk 205. Generally, the heatsink 230 is positioned in the middle of the top surface 210 of the disk205. The heat sink 230 has an effective center 235. The effective center235 is the center of the portion of the heat sink 230 without anyprotrusions (none shown in FIG. 2A, as opposed to FIG. 2C). If the heatsink 235 is a perfect conical frustum (a portion of a solid, such as acone, that lies between two parallel planes cutting it), the effectivecenter is the center of the conical frustum.

The heat sink 230 can be made of any plasmonic material. In embodiments,the heat sink can be made of gold (Au), silver (Ag), copper (Cu),aluminum (Al), and alloys thereof. The heat sink 230 and the disk 205can be made of the same or different materials. Generally, the heat sink230 has to have a thickness that is great enough that it can contact thewrite pole (another structure within the head). In embodiments, the heatsink 230 can have a thickness of about 130 nm.

The NFT 200 can also be described as having a peg axis 240, which can bedefined by the location of the peg 225 adjacent the side surface 215 ofthe disk 205. In an embodiment, the peg axis 240 can be defined by aplane that cuts the disk 205 and the peg 225 in half perpendicular to asubstrate upon which they are located. Perpendicular to the peg axis isthe non-peg axis 245.

In embodiments, the effective center 235 of the heat sink 230 ispositioned at about the center 220 of the disk 205. As can be seen fromFIG. 2A, if the heat sink 230 were to be placed back on the top surface210 of the disk 205 (by following the two arrows in FIG. 2A), theeffective center 235 of the heat sink 230 would be positioned at aboutthe center 220 of the disk 205. In embodiments, at about the center 220of the disk 205 means that the effective center 235 of the heat sink 230is centered at the center 220 of the disk 205. In embodiments, theeffective center 235 of the heat sink 230 and the center 220 of the disk205 are not more than about 8 nm apart; in embodiments not more thanabout 6 nm apart; and in embodiments not more than about 5 nm apart.

FIG. 2B shows a top down view of the NFT 200. Like components arenumbered similarly to FIG. 2A. The NFT 200 in FIG. 2B shows the diameterof the disk D_(d) and the effective diameter of the heat sink HS_(d).The heat sink 230 has an effective diameter HS_(d), the effectivediameter is relevant to the surface of the heat sink 230 that isadjacent the disk 205, not the top surface of the heat sink. Theeffective diameter HS_(d) is the diameter of the portion of the heatsink 230 without any protrusions (none shown in FIG. 2A, as opposed toFIG. 2C). If the heat sink 235 is a perfect conical frustum, theeffective diameter is the diameter of the conical frustum. Inembodiments, the diameter of the disk D_(d) can range from about 150 nmto about 350 nm; in embodiments from about 225 nm to about 275 nm; inembodiments from about 240 nm to about 260 nm; and in embodiments it isabout 250 nm. In embodiments, the effective diameter of the heat sinkHS_(d) can range from about 100 nm to about 300 nm; in embodiments fromabout 175 nm to about 225 nm; in embodiments from about 190 nm to about210 nm; and in embodiments it is about 200 nm.

FIG. 2C shows a top down view of an NFT 201 that includes a heat sink231 that includes a main portion 250 and a tip portion 255. The tipportion 255, when included, can be located in the region of the peg 225.In embodiments, the tip portion 255 can be located proximate the peg225. The tip portion 255 is the portion of the heat sink 231 thatextends from the conical frustum portion of the heat sink 231. Theconical frustum portion of the heat sink 231 can be defined as theportion within the circumference c. Generally, the tip portion 255 has asubstantially triangular shape and extends away from the main portion250 or the conical frustum portion of the heat sink 231. The portion ofthe tip portion 255 that extends away from the main portion 250 can bedescribed as having a length l, or extending away a certain distance. Inembodiments, the tip portion can extend away from the main portion about5 nm to about 25 nm; or about 10 nm to about 20 nm.

Methods of forming optical transducers, such as NFTs are also describedherein. It should also be noted that methods disclosed herein can beutilized to make features and/or portions of devices having any shapes,not just circular shapes. Although exemplary methods are illustratedherein using circular shapes, this should not be taken as limiting offeature shapes that can be formed using disclosed methods. FIGS. 3A-3Gillustrate an exemplary article at various stages of manufacture. Eachof FIGS. 3A-3G contains three figures, the one on the left is a crosssection of the portion of the article that eventually makes up the diskportion of the device; the one in the middle is a cross section of theportion of the article that eventually makes up the peg portion of thedevice; and the one on the right is a top down view of the wholearticle.

FIG. 3A shows a substrate 300 a upon which a first photoresist mask 305has been formed. The photoresist mask 305 has inside edges 307, whichdefine a first aperture 308. The first aperture 308 can be described ashaving a circular portion 308 a connected to a rectangular portion 308b. The first aperture 308 can also be described as having a width w₁.Generally, the width w₁ can be at least about 100 nm larger than thediameter of the disk that is being formed. In embodiments, the width w₁can be from about 150 nm to about 500 nm, or about 250 nm to about 400nm. The maximum width of the first aperture 308 can generally be limitedto a width that will afford structural integrity so that the secondphotoresist mask (discussed below) won't collapse.

FIG. 3B illustrates the article after completion of the next step,formation of a second photoresist mask 310 on the first photoresist mask305. The second photoresist mask 310 has inside edges 311 that define asecond aperture 313. The second aperture 313 can be described as havinga circular portion 313 a connected to a rectangular portion 313 b. Thesecond aperture 313 can also be described as having a width w₂. Thewidth w₂ of the second aperture 313 is less than or smaller than thewidth w₁ of the first aperture 308. Generally, the second width w₂ canrange from about 150 nm to about 350 nm.

The materials of the first photoresist mask 305 and the secondphotoresist mask 310 can be those generally utilized, including forexample polymethylmethacryalte (PMMA), or high performance electron beamresists such as ZEP520 (Zeon Corporation, Tokyo, Japan). The techniquesused to form the first and second apertures 308 and 313 are alsogenerally known and include formation of layers, masking, and exposingsteps.

FIG. 3C shows the article after the next step, deposition of the NFTmaterial 315. The NFT material can be deposited in at least the secondaperture 313. The NFT material 315 can be deposited so that it coats atleast a portion of the top surfaces of the second photoresist mask 310.The NFT material 315 can also form inside edges 317 on the inside edges311 of the second photoresist mask 310. Once the NFT material 315 isdeposited in the second aperture 313 it will generally form what willultimately become the disk 320 a and the peg 320 b. Completion of thisstep can form at least a disk portion of a NFT (a peg portion of a NFTcan also be formed). The disk portion will have a center (as discussedabove).

The NFT material can generally be any plasmonic material. Exemplarymaterials that can be utilized for the NFT material include, forexample, gold (Au), silver (Ag), copper (Cu), aluminum (Al), and alloysthereof. In exemplary embodiments, alloys of gold, including thosediscussed in co-pending, commonly assigned U.S. patent application Ser.No. 13/032,709, filed on Feb. 23, 2011; can be utilized. The NFTmaterial 315 can be deposited using any commonly utilized techniquesincluding for example E-beam evaporation, Ion beam deposition, chemicalvapor deposition (CVD), physical vapor deposition (PVD). In embodiments,the NFT material 315 can be deposited using E-beam evaporation.

FIG. 3D shows the article after completion of the next step,directionally depositing a cover material 325 on at least the insideedges of at least the NFT material 315. In embodiments, the covermaterial 325 can be deposited on the inside edges 317 of the NFTmaterial 315, the inside edges 311 of the second photoresist mask 310,the inside edges 307 of the first photoresist mask 305, and at least aportion of the NFT material 315. Deposition of the cover material 325defines a third aperture 327. The third aperture 327 can be described ashaving only a substantially circular portion. The cover material 325 canbe deposited in such a way that it sealed the rectangular shaped portionof the second aperture (as seen in the middle portion of FIG. 3D). Thisultimately allows the peg of the NFT to have a thickness that isunchanged by further deposition steps, because the heat sink materialwill not be deposited on the peg area of the disk material. The thirdaperture 327 can also be described as having a width w₃. The width w₃ ofthe third aperture 327 is less than or smaller than the widths w₁ andw₂, of both the first and second apertures 308 and 313. Generally, thethird maximum width w₃ can range from about 100 nm to about 300 nm.

FIG. 3E further illustrates directional deposition. In directionaldeposition, the direct source of the deposited material (for example anion beam in ion beam deposition (IBD), or an E-beam in E-beamevaporation) is not located directly above the article upon which it isto be deposited, but at an angle from the surface. Directionaldeposition can be further described by describing the angle ofdeposition. As seen in FIG. 3E, the surface of the NFT material 315defines a plane (as shown by the dashed line), the directionaldeposition of this step can be carried out an angle α from the surfaceof the NFT material 315. In embodiments, the angle α can be less than orequal to about 60°; or less than or equal to about 45°; or less than orequal to about 35°; or about 30°.

Directional deposition can be carried out using various depositiontechniques, including for example directional ion beam deposition (IBD),E-beam evaporation. The material that can be deposited in this step isnot generally limited, and can be most any material. Exemplary materialsthat can be deposited in this step include, for example, copper (Cu),gold (Au), or aluminum (Al). The directionality of the deposition can beobtained by tilting the wafer, tilting the ion beam (in the case ofIBD), or a combination thereof.

FIG. 3F shows the article after completion of the next step, depositionof a heat sink material 330. The heat sink material 330 can generally bedeposited in at least the third aperture 327. In embodiments, the heatsink material 330 can be deposited in the third aperture 327 and on atleast part of the surface of the cover material 325. Once the heat sinkmaterial 330 is deposited in the third aperture 327 it will generallyform what will ultimately become the heat sink 335. The heat sinkmaterial can generally be any plasmonic material (for example Cu, Ag,Au, Al, or alloys thereof). Because of the way in which the covermaterial 325 and the NFT material 315 are deposited on the inside edgesof various structures, the heat sink 335 will generally have asubstantially conical frustum shape. The heat sink 335 need not beexactly a conical frustum, but it can have the general shape of aconical frustum. Because of the covering of the rectangular shapedportion (or peg portion) of the second aperture 313, the heat sink 335can have a portion that extends out from the substantially conicalfrustum shape towards the rectangular shaped portion of the secondaperture 313; this portion of the heat sink 335 can be referred to asthe tip portion (as discussed above). Completion of this step can form aheat sink, which can be characterized as having an effective center (asdiscussed above with respect to FIG. 2A). In embodiments, the effectivecenter of the heat sink and the center of the disk can be not more than10 nm apart, not more than 8 nm apart, or not more than 5 nm apart.

FIG. 3G shows the article after completion of the next step, removal ofsome of the structures. In embodiments, at least a portion of the heatsink material 330, at least a portion of the cover material 325, atleast a portion of the NFT material 315, at least a portion of thesecond photoresist mask 310, at least a portion of the first photoresistmask 305, or some combination thereof can be removed during this step.In embodiments, at least a portion of the heat sink material 330, atleast a portion of the cover material 325, at least a portion of the NFTmaterial 315, at least a portion of the second photoresist mask 310, andat least a portion of the first photoresist mask 305 can be removedduring this step. In embodiments, at least a portion of the heat sinkmaterial 330, substantially of the cover material 325, at least aportion of the NFT material 315, substantially all of the secondphotoresist mask 310, and substantially all of the first photoresistmask 305 can be removed during this step. In embodiments, substantiallyall of the heat sink material 330 except that which formed the heat sink335, substantially of the cover material 325, substantially all of theNFT material 315 except that which formed the disk 320, substantiallyall of the second photoresist mask 310, and substantially all of thefirst photoresist mask 305 can be removed during this step. Removal ofthe various layers can be accomplished using commonly utilizedtechniques, including, for example chemical etching, reactive ionetching (RIE), chemical mechanical polishing (CMP). In embodiments, asingle liftoff process can remove all of the material deposited duringthe method except that which formed the disk, peg, and heat sink.

NFTs disclosed herein and methods of forming them can provide NFTs withheat sinks that are more advantageously aligned with the disk of theNFT. This can be advantageous because the coupling efficiency of theheat sink to the disk of the NFT can be better when it is betteraligned. Processes described herein can also be further advantageousbecause they offer less processing steps than other methods.

EXAMPLE

While the present disclosure is not so limited, an appreciation ofvarious aspects of the disclosure will be gained through a discussion ofthe example provided below.

A first photoresist layer was deposited on a substrate by spin-coatingMMA EL9 (9% MMA (methyl methacrylate) in ethyl lactate purchased fromMicroChem Corp., Newton, Mass.) 200-500 nm thick. The coated MMA EL9 wasthen baked at about 180° C. for about three minutes. Next, the secondphotoresist layer was deposited on the first photoresist layer byspin-coating MW 495k polymethylmethacrylate (PMMA) on the MMA EL9 atabout 30 to 200 nm thick. The article was then baked at about 180° C.for about three minutes. The article was then exposed to E-beamradiation using a Gaussian beam system (Vistec VB6, Vistec Lithography,Inc. Watervliet, N.Y.) operating at 100 kV and 5-10 nA. The dose used inthe peg area was about 2000 μC/cm² (a single beam pass was applied inorder to achieve as narrow a peg width as possible) and the dose used inthe disk area was about 1000 μC/cm². The first and second photoresistlayers were then developed with a mixed solvent of methyl isobutylketone (MIBK) and isopropanol (IPA) (MIBK:IPA=1:3 in volume) and thenrinsed with IPA. FIG. 4A shows a cross section of the article aftercompletion of this step.

Next, the NFT material, gold (Au) was deposited in an evaporator. Thegold was deposited to a thickness of about 20 nm to about 30 nm. FIG. 4Bshows the article after completion of this step. After that, copper (Cu)was deposited at a 30° angle using IBD. The Cu was deposited to athickness of about 40 nm. FIG. 4C shows a top view of the article aftercompletion of this step; and FIG. 4D shows a cross section view at thepeg area.

Next, the heat sink material, gold (Au) was deposited using IBD to athickness of about 130 nm. FIG. 4E shows a cross section at the diskarea and FIG. 4F shows a cross section at the peg area. Next, everythingbut the NFT (the disk and the peg) and the heat sink were lifted off.FIG. 4G shows a perspective view of the article; FIG. 4H shows thediameter of the disk, 0.198 micrometers; and FIG. 4I shows the diameterof the heat sink 0.122 micrometers.

Thus, embodiments of LIGHT DELIVERY WAVEGUIDES are disclosed. Theimplementations described above and other implementations are within thescope of the following claims. One skilled in the art will appreciatethat the present disclosure can be practiced with embodiments other thanthose disclosed. The disclosed embodiments are presented for purposes ofillustration and not limitation.

What is claimed is:
 1. A near field transducer (NFT) comprising: a disk,the disk having a top surface, a side surface, and a center; a peg, thepeg positioned adjacent the side surface of the disk; and a heat sink,the heat sink positioned on the top surface of the disk, and the heatsink having an effective center, wherein the NFT has a peg axis, whichis defined by the location of the peg adjacent the side surface of thedisk, and a non-peg axis, which is perpendicular to the peg axis, andwherein the effective center of the heat sink is positioned at about thecenter of the disk.
 2. The NFT according to claim 1, wherein theeffective center of the heat sink and the center of the disk are notmore than 8 nm apart in the direction of the non-peg axis.
 3. The NFTaccording to claim 1, wherein the effective center of the heat sink andthe center of the disk are not more than 6 nm apart in the direction ofthe non-peg axis.
 4. The NFT according to claim 1, wherein the effectivecenter of the heat sink and the center of the disk are not more than 5nm apart in the direction of the non-peg axis.
 5. The NFT according toclaim 1, wherein the heat sink comprises main portion and a tip portion,the tip portion being located proximate the peg.
 6. The NFT according toclaim 1, wherein the disk and the peg are a continuous structure.
 7. TheNFT according to claim 1, wherein the disk has a diameter of about 250nm and the heat sink has an effective diameter of about 200 nm.
 8. TheNFT according to claim 1, wherein the disk and the peg comprise gold(Au), silver (Ag), copper (Cu), aluminum (Al), or alloys thereof.
 9. TheNFT according to claim 1, wherein the heat sink comprises gold (Au),silver (Ag), copper (Cu), aluminum (Al), or alloys thereof.
 10. A nearfield transducer (NFT) comprising: a disk, the disk having a topsurface, a side surface, and a center; a peg, the peg positionedadjacent the side surface of the disk; and a heat sink, the heat sinkcomprising a main portion and a tip portion, and the heat sink beingpositioned on the top surface of the disk, wherein the NFT has a pegaxis, which is defined by the location of the peg adjacent the sidesurface of the disk, and a non-peg axis, which is perpendicular to thepeg axis, and wherein the tip portion of the heat sink is locatedsubstantially in the direction of the peg axis.
 11. The NFT according toclaim 10, wherein the main portion of the heat sink has a circumferenceand the tip portion extends from about 5 nm to about 25 nm away from thecircumference.
 12. The NFT according to claim 10, wherein the mainportion of the heat sink has a circumference and the tip portion extendsfrom about 10 nm to about 20 nm away from the circumference.
 13. The NFTaccording to claim 10, wherein the main portion of the heat sink has acenter, and wherein the center of the main portion of the heat sink ispositioned at about the center of the disk.
 14. The NFT according toclaim 13, wherein the center of the main portion of the heat sink andthe center of the disk are not more than 8 nm apart in the direction ofthe non-peg axis.
 15. The NFT according to claim 13, wherein the centerof the main portion of the heat sink and the center of the disk are notmore than 5 nm apart in the direction of the non-peg axis.
 16. The NFTaccording to claim 10, wherein the disk and the peg comprise gold (Au),silver (Ag), copper (Cu), aluminum (Al), or alloys thereof.
 17. The NFTaccording to claim 10, wherein the heat sink comprises gold (Au), silver(Ag), copper (Cu), aluminum (Al), or alloys thereof.
 18. A disc drivecomprising: a magnetic head comprising: a near field transducer (NFT)comprising: a disk, the disk having a top surface, a side surface, and acenter; a peg, the peg positioned adjacent the side surface of the disk;and a heat sink, the heat sink positioned on the top surface of thedisk, and the heat sink having an effective center, wherein the NFT hasa peg axis, which is defined by the location of the peg adjacent theside surface of the disk, and a non-peg axis, which is perpendicular tothe peg axis, and wherein the effective center of the heat sink ispositioned at about the center of the disk.
 19. The disc drive accordingto claim 18, wherein the effective center of the heat sink and thecenter of the disk are not more than 6 nm apart in the direction of thenon-peg axis.
 20. The disc drive according to claim 18, wherein the diskhas a diameter of about 250 nm and the heat sink has an effectivediameter of about 200 nm.